Geologists, geophysicists and petroleum engineers use models, including computerized models, of the earth's shell to plan exploration and production of hydrocarbons and, to a lesser extent, other minerals. As hydrocarbons become more and more scarce, the accuracy of the computerized models becomes increasingly important to limiting the cost of locating and producing hydrocarbons and the associated cost of hydrocarbon products, such as gasoline and heating oil.
Interpretation of geophysical and geological data stored in a computerized model relies on the ability of the model to be displayed in such a way that the information contained in the model can be discerned and edited.
The Interactive Geometric Modeling library (IGM) (see U.S. Pat. No. 6,191,787 to Lu, et al.) integrates a geometry engine and a graphics engine. This integration provides a high level interface that supports interactive feature-based 3D geoscience geometric model building, rendering and editing.
A scenegraph is a representation of a scene by a graphics engine. Efficient scenegraph construction and maintenance directly affect the performance of an interactive system. This patent application describes several new techniques for constructing and maintaining a scenegraph, which greatly enhances performance of and adds new functionality to the IGM.
The geometry engine that the IGM uses is the Geometry Query Interface (GQI) (see U.S. Pat. No. 6,128,577 to Assa, et al.). The GQI is a layer built on top of a geometry kernel called “Shapes” from XOX, Inc. The graphics engine is called Open Inventor. The IGM integrates the two engines to enable interactive feature-based geometric modeling.
The GQI builds geometric models via Irregular Space Partitioning using Boolean operations. The resulting model is a boundary representation (b-rep) model. The GQI provides feature-based modeling for geoscience applications, where features are entities of interest to an end user concerning group geometric and topological elements in a model.
Several factors have to be considered for constructing and maintaining scenegraphs for building geoscience models. The process and the generated geoscience geometric models are different from those in traditional CAD industry. Some of these differences that relate to this invention are listed below. These differences affect the manner of constructing and maintaining the scenegraph for rendering.
First, models are built via irregular space partitioning where input features are split into pieces, while CAD industry typically uses Constructive Solid Geometry where input features are combined via Boolean operations. Secondly, the material properties in a geoscience geometric model are typically space changing and are attached at the feature level, while in CAD industry each element in a model typically has a constant material property. Third, a crack is normal in a geoscience model, while a crack may be a defect in a CAD model.
Similar to the needs of users in the CAD industry, a geoscience user wants to be able to interact with and maintain the identities of input features and to assign and interact with new features.
For geoscience applications, the following two types of views are typically required. The first type is surface view that renders surface cells or features in the model. The second type is volume view that renders the volume cells or features in the model. A surface cell has its own identity. It also serves as a boundary cell for two volumes that share it. A user may also want combinations of the two types. Consequently, there is more than one graphical representation for the same geometric model.
Finally, software related to geoscience applications typically consume considerable computer resources, oftentimes requiring powerful workstations that are not easily moved. However, it would be desirable to have the capability mentioned above at field locations. There is, therefor, a need in the art to increase the efficiency of geoscience software to the point that it can be installed on normal mobile computing devices, such as laptop computers.